1. Field of the Invention
The present invention relates to medical equipment and more specifically to means for providing treatment of a biological object with mixed gases containing nitrogen oxide. The invention is suitable for treating various pathological processes in general, abdominal, thoracic, purulent, vascular and anaplastic surgery, oncology, urology, combustiology, dentistry, ophthalmology, neurosurgery and other fields of medicine.
2. State of the Art
A method for preparing a mixture containing air and nitrogen oxide for treating medical pathologies by directly supplying the mixture to a certain patient's organ, taught in U.S. Pat. No. 5,396,882, Cl. A 61 M 11/00, publ. Mar. 14, 1995, comprises the steps of injecting air through an inlet channel into a spark-discharge chamber in the system; applying a high-voltage potential to a set of electrodes separated by an air gap and accommodated in the spark-discharge chamber, the high-voltage potential having an adequate peak value to generate a spark discharge in the air gap; producing a mixture of air with nitrogen oxide by the spark discharge between the electrodes under the effect of the high-voltage potential, and immediately supplying the produced air/nitrogen oxide mixture via an outlet system adapted to instantly deliver the mixed gas to a certain organ of a patient's body.
The prior art method is implemented in a system for continuously producing a mixture containing air and nitrogen oxide and intended for treating medical pathologies which need direct delivery of the mixture to an organ of a patient's body, the system comprising a spark-discharge chamber with a pair of electrodes separated by an air gap to produce nitrogen oxide by a spark discharge between the electrodes; an electric circuit for applying a high-voltage potential to the electrodes, said high-voltage potential having an adequate peak value to generate a spark discharge in the air gap; an inlet channel for supplying air into the spark-discharge chamber to produce air/nitrogen oxide mixture therein; an outlet system for directing the produced air/nitrogen oxide mixture to an organ of a patient body, the outlet system and the spark-discharge chamber being dimensioned and arranged so that to provide immediate distribution of the produced mixture from the outlet.
However, the prior art method and apparatus can be practiced only using a spark discharge as an electric discharge to produce the air/nitrogen oxide mixture.
The above method and apparatus suffer the following disadvantages:
1. Production of nitrogen oxide is intermittent because the high voltage feeding the electrical discharge is applied to the electrodes at a frequency of 50 or 60 Hz.
2. The electrodes are extremely prone to erosion which is unavoidable in spark discharges, this reducing the operation life of the apparatus and contaminating the produced air/nitrogen oxide mixture with particles of the electrode material.
3. Ozone molecules are formed in the spark discharge due to both ultra-violet radiation and impacts of electrons (since the energy of electrons is rather high) in accordance with the following reactions (where M is any reacting particle):e+O2→O+O−e+O2→O+O+eO+O2+M→O3+Mtherefore, the produced mixed gas will contain ozone molecules because the spark discharge is incapable of heating gas to the temperature of ozone decomposition and turning back to oxygen.
4. The apparatus that uses a spark discharge for producing air/nitrogen oxide mixture will inevitably be a source of radio-frequency noise (both on air and in line), this causing a problem of electromagnetic compatibility with electronic equipment used in resuscitation departments and surgery rooms.
5. Restricted content of nitrogen oxide in the mixed gas produced by a spark discharge may reduce efficiency of managing some pathologic processes, such as septic and chronic wounds, necrotic injures of tissues, etc.
The aforementioned deficiencies can be overcome by the use of a stationary arc discharge supported by a high-frequency or direct current in the apparatus instead of the spark discharge, preferably by the use of a direct current (dc) discharge to alleviate the magnetic compatibility problem.
However, the use of the dc arc discharge (along with high-frequency one) is infeasible in the prior art apparatus due to the lack of a system for forced cooling of the electrodes and air/nitrogen oxide mixture produced by such discharge.